Sentences not of ephemeral, but of eternal,
efficacy. --Sir J.
Stephen.
[1913 Webster]

{Ephemeral fly} (Zo["o]l.), one of a group of neuropterous
insects, belonging to the genus {Ephemera} and many allied
genera, which live in the adult or winged state only for a
short time. The larv[ae] are aquatic; -- called also {day
fly} and {May fly}.
[1913 Webster]

Ephemeral — E*phem er*al, n. Anything lasting but a day, or a brief time; an ephemeral plant, insect, etc. [1913 Webster] … The Collaborative International Dictionary of English

ephemeral — I adjective brevis, brief, caducous, caducus, continuing for a short time, deciduous, disappearing, elusive, enduring only a very short time, ephemerous, evanescent, existing for a short time, fleeting, fugacious, fugitive, hurried, impermanent,… … Law dictionary

ephemeral — [[t]ɪfe̱mərəl[/t]] ADJ GRADED If you describe something as ephemeral, you mean that it lasts only for a very short time. [FORMAL] He talked about the country s ephemeral unity being shattered by the defeat... These paintings are in some ways a… … English dictionary